<html>

    <head>
        <!-- bootstrap 4.x is supported. You can also use the bootstrap css 3.3.x versions -->
        <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-beta/css/bootstrap.min.css">
        <link href="https://cdnjs.cloudflare.com/ajax/libs/bootstrap-fileinput/4.4.9/css/fileinput.min.css" media="all"
                                                                                                            rel="stylesheet" type="text/css" />
        <!-- if using RTL (Right-To-Left) orientation, load the RTL CSS file after fileinput.css by uncommenting below -->
        <!-- link href="https://cdnjs.cloudflare.com/ajax/libs/bootstrap-fileinput/4.4.9/css/fileinput-rtl.min.css" media="all" rel="stylesheet" type="text/css" /-->
        <script src="https://code.jquery.com/jquery-3.2.1.min.js"></script>
        <!-- piexif.min.js is needed for auto orienting image files OR when restoring exif data in resized images and when you 
            wish to resize images before upload. This must be loaded before fileinput.min.js -->
            <script src="https://cdnjs.cloudflare.com/ajax/libs/bootstrap-fileinput/4.4.9/js/plugins/piexif.min.js"
                    type="text/javascript"></script>
            <!-- sortable.min.js is only needed if you wish to sort / rearrange files in initial preview. 
                This must be loaded before fileinput.min.js -->
                <script src="https://cdnjs.cloudflare.com/ajax/libs/bootstrap-fileinput/4.4.9/js/plugins/sortable.min.js"
                        type="text/javascript"></script>
                <!-- purify.min.js is only needed if you wish to purify HTML content in your preview for 
                    HTML files. This must be loaded before fileinput.min.js -->
                    <script src="https://cdnjs.cloudflare.com/ajax/libs/bootstrap-fileinput/4.4.9/js/plugins/purify.min.js"
                            type="text/javascript"></script>
                    <!-- popper.min.js below is needed if you use bootstrap 4.x. You can also use the bootstrap js 
                        3.3.x versions without popper.min.js. -->
                        <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.11.0/umd/popper.min.js"></script>
                        <!-- bootstrap.min.js below is needed if you wish to zoom and preview file content in a detail modal
                            dialog. bootstrap 4.x is supported. You can also use the bootstrap js 3.3.x versions. -->
                            <script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-beta/js/bootstrap.min.js"
                                    type="text/javascript"></script>
                            <!-- the main fileinput plugin file -->
                            <script src="https://cdnjs.cloudflare.com/ajax/libs/bootstrap-fileinput/4.4.9/js/fileinput.min.js"></script>
                            <!-- optionally if you need a theme like font awesome theme you can include it as mentioned below -->
                            <script src="https://cdnjs.cloudflare.com/ajax/libs/bootstrap-fileinput/4.4.9/themes/fa/theme.js"></script>
                            <!-- optionally if you need translation for your language then include  locale file as mentioned below -->
                            <script src="https://cdnjs.cloudflare.com/ajax/libs/bootstrap-fileinput/4.4.9/js/locales/(lang).js"></script>
    </head>

    <body style="width:100%;height:100%;text-align:center;">
        <div style="width:60%;height:30%;text-align:center;">
            <form action='#' method="post" enctype="multipart/form-data">
                <input id="file" name="file" type="file" class="file" data-msg-placeholder="choose a file">
            </form>
        </div>
    </body>

    <script>
        var hexcase = 0; /* hex output format. 0 - lowercase; 1 - uppercase */
var chrsz = 8; /* bits per input character. 8 - ASCII; 16 - Unicode */
/*
 *
 * The main function to calculate message digest
 *
 */
function hex_sha1(s) {
    return binb2hex(core_sha1(AlignSHA1(s)));
}

/*
 *
 * Perform a simple self-test to see if the VM is working
 *
 */
function sha1_vm_test() {
    return hex_sha1("abc") == "a9993e364706816aba3e25717850c26c9cd0d89d";
}

/*
 *
 * Calculate the SHA-1 of an array of big-endian words, and a bit length
 *
 */
function core_sha1(blockArray) {
    var x = blockArray; // append padding
    var w = Array(80);
    var a = 1732584193;
    var b = -271733879;
    var c = -1732584194;
    var d = 271733878;
    var e = -1009589776;

    for (var i = 0; i < x.length; i += 16) // 每次处理512位 16*32
    {
        var olda = a;
        var oldb = b;
        var oldc = c;
        var oldd = d;
        var olde = e;
        for (var j = 0; j < 80; j++) // 对每个512位进行80步操作
        {
            if (j < 16)
                w[j] = x[i + j];
            else
                w[j] = rol(w[j - 3] ^ w[j - 8] ^ w[j - 14] ^ w[j - 16], 1);
            var t = safe_add(safe_add(rol(a, 5), sha1_ft(j, b, c, d)), safe_add(safe_add(e, w[j]), sha1_kt(j)));
            e = d;
            d = c;
            c = rol(b, 30);
            b = a;
            a = t;
        }

        a = safe_add(a, olda);
        b = safe_add(b, oldb);
        c = safe_add(c, oldc);
        d = safe_add(d, oldd);
        e = safe_add(e, olde);
    }
    return new Array(a, b, c, d, e);
}

/*
 *
 * Perform the appropriate triplet combination function for the current
 * iteration
 *
 * 返回对应F函数的值
 *
 */
function sha1_ft(t, b, c, d) {
    if (t < 20)
        return (b & c) | ((~b) & d);
    if (t < 40)
        return b ^ c ^ d;
    if (t < 60)
        return (b & c) | (b & d) | (c & d);
    return b ^ c ^ d; // t<80
}

/*
 *
 * Determine the appropriate additive constant for the current iteration
 *
 * 返回对应的Kt值
 *
 */
function sha1_kt(t) {
    return (t < 20) ? 1518500249 : (t < 40) ? 1859775393 : (t < 60) ? -1894007588 : -899497514;
}

/*
 *
 * Add integers, wrapping at 2^32. This uses 16-bit operations internally
 *
 * to work around bugs in some JS interpreters.
 *
 * 将32位数拆成高16位和低16位分别进行相加，从而实现 MOD 2^32 的加法
 *
 */
function safe_add(x, y) {
    var lsw = (x & 0xFFFF) + (y & 0xFFFF);
    var msw = (x >> 16) + (y >> 16) + (lsw >> 16);
    return (msw << 16) | (lsw & 0xFFFF);
}

/*
 *
 * Bitwise rotate a 32-bit number to the left.
 *
 * 32位二进制数循环左移
 *
 */
function rol(num, cnt) {
    return (num << cnt) | (num >>> (32 - cnt));
}

/*
 *
 * The standard SHA1 needs the input string to fit into a block
 *
 * This function align the input string to meet the requirement
 *
 */
function AlignSHA1(str) {
    var nblk = ((str.length + 8) >> 6) + 1,
        blks = new Array(nblk * 16);

    for (var i = 0; i < nblk * 16; i++)
        blks[i] = 0;

    for (i = 0; i < str.length; i++)
        blks[i >> 2] |= str.charCodeAt(i) << (24 - (i & 3) * 8);
    blks[i >> 2] |= 0x80 << (24 - (i & 3) * 8);
    blks[nblk * 16 - 1] = str.length * 8;
    return blks;

}

/*
 *
 * Convert an array of big-endian words to a hex string.
 *
 */
function binb2hex(binarray) {
    var hex_tab = hexcase ? "0123456789ABCDEF" : "0123456789abcdef";
    var str = "";
    for (var i = 0; i < binarray.length * 4; i++) {
        str += hex_tab.charAt((binarray[i >> 2] >> ((3 - i % 4) * 8 + 4)) & 0xF) +
            hex_tab.charAt((binarray[i >> 2] >> ((3 - i % 4) * 8)) & 0xF);
    }
    return str;
}
    </script>

</html>
